Antenna arrays, including focal plane image sensors such as charge coupled device (CCD) diode arrays, are used in a number of signal transmission and receiving applications as well as imaging applications and over a large range of frequencies of the electromagnetic spectrum. Traditionally, signals received at an antenna array were electronically amplified and converted to an intermediate frequency for subsequent electronic signal processing.
More recently, with a growing need for increased bandwidth and speed, optical processing techniques have been implemented for the processing of signals from antenna arrays and imaging systems. For such techniques, electro-optic modulators relying on zero-order interferometry, such as Mach-Zender modulators, or those utilizing polarization rotation as the basis for electro-optic modulation have been used to convert detected electrical signal into the optical domain by using the antenna array signals to modulate optical carrier signals in optical waveguides. For such applications, it has been common to use electronic low noise amplifiers and (tunable) filters to process the signals from the antenna arrays and image sensors prior to electro-optic modulation.
Such prior electro-optic modulation techniques have been useful for some application but have been limited for other applications by exhibiting low bandwidth, low gain, and high noise figures. Additionally, such prior art modulation techniques have required relatively high power levels for sufficient modulation—on the order of 1 Watt of microwave power and have required large size requirements (or form factors) due to the significant optical paths required for sufficient modulation to take place.
What is needed therefore are systems, apparatus, and methods that can provide higher bandwidth, higher gain, and lower noise figures as well as lower form factors.